Kay Hymowitz has a theory that's worth reading in the most recent issue of City Journal:
What two-America talk doesn't get is just how much these ominous trends are entangled with the collapse of the nuclear family. While Americans have been squabbling about gay marriage, they have managed to miss the real marriage-and-social-justice issue, one that affects far more people and threatens to undermine the American project. We are now a nation of separate and unequal families not only living separate and unequal lives but, more worrisome, destined for separate and unequal futures.
